1. Technical Field
The present disclosure relates to an image processing apparatus that can obtain surface topography (micro-geometry) information that surpasses information to be normally obtained by an image sensor from a two-dimensional light intensity image.
2. Description of the Related Art
In the field of endoscopes that capture an image of an organism's organ by irradiating the surface of the organ, which is covered with a semi-transparent mucosa, with light, the surface texture and an image of a blood vessel under the surface need to be checked with regular reflection (i.e., specular reflection) from the surface avoided. To do that, a polarizing endoscope that uses polarized light and polarized image capturing has been proposed. For example, Japanese Laid-Open Patent Publication No. 2009-246770 discloses an endoscope that includes a polarized light source that irradiates an object with light having a particular polarization component and a light receiving section and that generates a shape variation image representing a variation in the surface shape of the object. The light receiving section of that endoscope receives light with a particular polarization component that is included in the light returning from the object and light with a different polarization component from the particular one that is also included in the returning light. The polarization image sensor disclosed in Japanese Laid-Open Patent Publication No. 2009-246770 includes an RGB color mosaic and polarizers, which are arranged so that their polarized light transmission axes face three different directions. Japanese Laid-Open Patent Publication No. 2009-246770 says that to allow the viewer to easily recognize the surface micro-geometry of the mucosa, in particular, a polarization property calculating section calculates a polarization orientation and can generate a two-dimensional distribution of surface tilt information.